Adding JPA Entities

pom.xml

@@ -23,10 +23,12 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-data-jpa</artifactId>
         </dependency>
+
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
+
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
@@ -37,6 +39,12 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>jakarta.persistence</groupId>
+            <artifactId>jakarta.persistence-api</artifactId>
+            <version>3.1.0</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/guru/springframework/spring6webapp/domain/Author.java

@@ -0,0 +1,48 @@
+package guru.springframework.spring6webapp.domain;
+
+import jakarta.persistence.*;
+import java.util.Set;
+
+@Entity // this annotation indicates that this class is a JPA entity
+public class Author {
+    @Id // This annotation indicates that this field is the primary key of the entity
+    @GeneratedValue (strategy = GenerationType.AUTO) // this annotation specifies that the primary key will be generated automatically
+    private Long idAuthor;
+    private String firstName;
+    private String lastName;
+
+    @ManyToMany(mappedBy = "authors") // this annotation indicates a many-to-many relationship with the Book entity
+    private Set<Book> books;
+
+    public Long getIdAuthor() {
+        return idAuthor;
+    }
+
+    public void setIdAuthor(Long idAuthor) {
+        this.idAuthor = idAuthor;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public Set<Book> getBooks() {
+        return books;
+    }
+
+    public void setBooks(Set<Book> books) {
+        this.books = books;
+    }
+}

src/main/java/guru/springframework/spring6webapp/domain/Book.java

@@ -0,0 +1,51 @@
+package guru.springframework.spring6webapp.domain;
+
+import jakarta.persistence.*;
+
+import java.util.Set;
+
+@Entity
+public class Book {
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long idBook;
+    private String title;
+    private String isbn;
+
+    @ManyToMany
+    @JoinTable(name ="author_book", joinColumns = @JoinColumn(name = "book_id"),
+    inverseJoinColumns = @JoinColumn(name = "author_id")) // This annotation defines the join table for the many-to-many relationship
+    private Set<Author> authors;
+
+    public Long getIdBook() {
+        return idBook;
+    }
+
+    public void setIdBook(Long idBook) {
+        this.idBook = idBook;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(String isbn) {
+        this.isbn = isbn;
+    }
+
+    public Set<Author> getAuthors() {
+        return authors;
+    }
+
+    public void setAuthors(Set<Author> authors) {
+        this.authors = authors;
+    }
+}

web/WEB-INF/web.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
+         version="4.0">
+</web-app>